[manager] Support deallocation of memory

[manager] Support deallocation of memory

Create a proper support for deallocation of memory by the manager which
for now will be done with destruction of manager or the model itself.

This frees all the memory involved in the model for inference or training.

See Also #974

**Self evaluation:**
1. Build test: [x]Passed [ ]Failed [ ]Skipped
2. Run test: [x]Passed [ ]Failed [ ]Skipped

Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>